Grant: Travel Awards - Institute Community Support

Glucose is the only energy source for the human brain under normal conditions. Fluctuation in glucose level can regulate many cognitive functions, including learning and memory. Dopamine (DA) neurons in the ventral tegmental area (VTA) play a critical role in reward learning and can serve as primary metabolic sensors. While early studies have indicated that alterations in VTA glucose can change dopamine output, little is known if changes in glucose concentrations influence excitatory synaptic transmission onto DA neurons in the VTA. Therefore, we investigated differing glucose concentration on synaptic transmission of putative VTA DA neurons in midbrain slices using whole cell path clamp. High glucose levels, typically used in slice electrophysiology experiments, decreased excitatory transmission onto DA neurons compared to a physiological brain glucose concentration that would occur after a meal. We also examined glucose effect on dopamine release in the nucleus accumbens (NAc) with in vivo fast scan cyclic voltammetry. We observed a decreased DA release with intra-VTA application of high glucose, suggesting glucose concentration modulates dopamine neuron outputs in the NAc. In conclusion, glucose modulates inputs and outputs of VTA DA neurons.